[Samba] Samba 3.x client -> Samba 2.2.x server authentication?

[kend at xanoptix.com]

Hey, all.  I've upgraded my workstation (Debian) to the Debian Samba 3.x
install.  I decided to start from scratch with my smb.conf, because I didn't
know enough to be wary of what parameters were deleted, etc.  So I put
password server = sambapdc
into my smb.conf, and figured it would "Just Work."  No dice.  A glance at
the log file shows"

[2003/10/15 12:11:08, 1] sam/idmap_tdb.c:db_idmap_init(331)
  idmap gid range missing or invalid
  idmap will be unable to map foreign SIDs

Some Googling showed this to be some sort of issue with the "passdb backend"
(which Debian set to "smbpasswd guest"), so I commented it out, thinking it
might be conflicting with the "password server" directive.  Nothing doing. 
Any hints?

Thanks,

Ken D'Ambrosio
Sr. SysAdmin,
Xanoptix, Inc.

P.S.  I have to assume that this has already been mentioned, but the smb.conf
manpage -- at least in the Debian version that I have -- has almost none of
the directives listed; an obvious editing boo-boo...